The present application relates generally to diagnostics for systems including a variable frequency drive configured to drive a motor. Variable frequency drives, sometimes referred to as a variable speed drives, may be utilized in connection with a variety of systems including HVACR systems such as air conditioning systems, heat pump systems and other refrigeration systems, air compressor systems, and other compressor drive systems. In such systems, variable frequency drives may be utilized to electrically drive motors that are, in turn, structured to drive a number of different mechanical loads including, for example, refrigerant compressors, condenser fans, cooling fans, air compressors and other types of fans and compressors. Utilization of variable frequency drives in such applications offers a number of benefits including those respecting energy efficiency and operational cost. Yet the presence of variable frequency drives presents additional potential failure modes. It can be complex, time consuming and expensive for a service technician to adequately diagnose such systems. Inadequate diagnostics may result in unnecessary replacement of functioning system components, repeated service events, or other undesirable service and maintenance complications. There remains a significant need for enhancements to diagnostics for such systems.